1. Field of the Invention
The present invention relates to a mechanism for holding a saw blade to the reciprocating plunger of a tool, such as a power tool. More particularly, the present invention relates to a self locking, quick-release blade clamp assembly that will accommodate blades of varying thickness.
2. Scope of the Prior Art
Saw blades of the type under consideration have a planar cutting portion with teeth extending along one edge of the blade from the outer end thereof. These blades also have an integral co-planar mounting portion with an aperture adjacent the inner end of the blade. Typically, the reciprocating plunger of a power tool that will utilize blades of this type includes an opening or cavity to receive the mounting portion of a selected blade. Normally the plunger includes a short cylindrical projection that extends into the cavity for interengagement with the aforementioned blade aperture. Conventional blade holders of the type under consideration use a screw for tightly clamping the blade to the tool plunger. Of course, tightening of the screw requires use of a separate tool, such as a screwdriver or Allen wrench.
Other forms of blade holders are known in the prior art that use cam to hold the blade in place. U.S. Pat. No. 4,106,181 to Mattchen discloses a quick-release mechanism including a cam to hold the blade in place. The cam rotates a handle. U.S. Pat. No. 5,443,276 to Nasser et al discloses a spring biased cam that is rotated by a knob. The knob protrudes from the side of the housing that holds the cam. The use of a side knob can be bulky and difficult to operate. In order to reduce the dimensions of the blade holder, the knob must be kept relatively small making it difficult to overcome the torsion of the spring. U.S. Pat. No. 5,722,309 to Seyerle discloses a blade holder that uses a pivoting cam to hold the blade. The cam is biased by a spring that is exposed to the outside of the holder so that it can be damaged during operation of the saw. In addition, the handle is relatively long and extends out from the saw. Because of its length, the handle can be damaged during operation thereby reducing the effectiveness of the holder. The devices shown in these patents also are either overly complicated or difficult to operate or easily damaged.